OptiStruct is a proven, modern structural solver with comprehensive, accurate and scalable solutions for linear and nonlinear
analyses across statics and dynamics, vibrations, acoustics, fatigue, heat transfer, and multiphysics disciplines.
The OptiStruct Example Guide is a collection of solved examples for various solution sequences and optimization types and provides
you with examples of the real-world applications and capabilities of OptiStruct.
Structure quarter symmetric pipe model with pretension bolt and a gasket seal, demonstrates the usage of gasket material
and gasket seal specific results for diagnostics.
The structural analyses of a cylinder head under various loading conditions can be accomplished by means of finite element
analysis using OptiStruct. The results, combined with each analysis concerning the different operating processes of the engine, can be separated
mainly into two parts.
This section presents optimized topology examples generated using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used as a design concept tool.
This section presents size (parameter) optimization examples solved using OptiStruct. Each example uses a problem description, execution procedures, and results to demonstrate how OptiStruct is used in size optimization.
This section presents shape optimization example problems, solved using OptiStruct. Each example uses a problem description, execution procedures and results to demonstrate how OptiStruct is used in shape optimization.
The examples in this section demonstrate how topography optimization generates both bead reinforcements in stamped
plate structures and rib reinforcements for solid structures.
The examples in this section demonstrate how the Equivalent Static Load Method (ESLM) can be used for the optimization
of flexible bodies in multibody systems.
The OptiStruct Example Guide is a collection of solved examples for various solution sequences and optimization types and provides
you with examples of the real-world applications and capabilities of OptiStruct.
The structural analyses of a cylinder head under various loading conditions can be accomplished by means of finite element
analysis using OptiStruct. The results, combined with each analysis concerning the different operating processes of the engine, can be separated
mainly into two parts.
The structural analyses of a cylinder head under various loading conditions can be
accomplished by means of finite element analysis using OptiStruct.
The results, combined with each analysis concerning the different operating processes of the
engine, can be separated mainly into two parts.
The capacity of gasket sealing mainly depends upon the pre-stressing of the bolts, which
are the source of the maximum external loading on the inner structure of the cylinder head.
The location of the weakest contact pressure on the raised portion of the gasket can be
transferred as a result of the effect of thermal stress or strain, which may cause the
increase in pressure and escaping of the gas.
Based on the above use case, Nonlinear Static Analysis is demonstrated for the Altair inline-four engine block model, as shown in Figure 1. The key features such as 3D pretension bolts, gasket material
modeling, friction contact and bore deformations are highlighted.
Note: There are a few
orphan grids in the model, which may lead to some differences in contour results when the
H3D results are plotted in HyperView. If results are different
from what is illustrated in this document, then mask the orphan grids in HyperView and then plot the contour again.
Model Description
The analytical procedure could further be divided into three load steps by means of the
superposition principle for simulating various operating processes of the engine, so the
structural analysis are composed of the outputs of these three load steps.
FE Model
Element Types
CHEXA
CTETRA
The linear material properties are:
MAT1
Young’s Modulus
21500 MPA
Poisson's Ratio
0.3
MGAASK
Direct Tensile Modulus
0.001
Transverse Shear Modulus
12000
Assembly Loadings
The major percentage of the loading applied to the engine is
the assembly loading. This mainly refers to the pre-stressing of the bolts, and it plays
an important role in preventing gas from escaping from the internal part of the
engine.
Thermal Loadings
In the case of thermal loadings, the nodal temperatures
resulting from the prescribed thermal analysis are assigned to all corresponding nodes of
the FEM model of the second cylinder head in order to calculate the thermal stress/strain
of the cylinder head structure.
Gas Pressure
The gas pressure created as a result of the firing of the spark
plug is imposed on the surface of the combustion chamber. However, the magnitude of the
gas pressure varies with different durations of the cycle. For the steady-state analysis,
the average gas pressure is introduced into the loading conditions for the simulation
here.
The nonlinear static analysis material properties are:
Case 1
Assembly Loadings
Applied pretension loading (41.25 KN) in head bolts